In an automobile reduction gearing is normally provided in the steering mechanism. Nowadays a power steering device is mostly equipped in an automobile to reduce force of wheel steering operation. In particular, the effectiveness of a power steering is more notable when an automobile is in a static status and tries to turn the steering wheel. Saving effort in steering by means of power steering makes the driver more comfortable, however, the turning angle is often made unconsciously too large or too small.
Such a situation may usually occur especially when making side parking or backing into the garage. Under Such circumstances , many trials have to be done sometimes for a young hand driver without experience. An experienced old hand driver may be able to park in position easily, but after positioning, he still has no idea about the turning angle of the front-wheels. Therefore, after parking or before driving out it is necessary to observe the position of the front wheels.
To overcome the above-mentioned defects, a great deal of creations and improvements have been made heretofore, such as Taiwanese Patent Application No. 77207046 entitled "Indicating Means for Turning Angle of Front-wheels of Automobile" and Application No. 83200296 for "Indicating Instrument for Turning Angle of Automobile Steering Wheel", etc. are the typical examples. However, these prior designs are not so ideal because, on the one hand, the constructions are too complicated to put in operation, and on the other hand, the costs are too high to be used. In consequence, they have not been generally used.